Arbitrage betting is the closest thing to free money in sports betting. When two sportsbooks disagree on the odds enough, you can bet both sides of an event and guarantee profit regardless of the outcome. No prediction required. No edge needed. Just math, speed, and discipline.

Professional arbers routinely extract $500-$5,000 per month with minimal risk. The concept is simple: if Sportsbook A offers the favorite at -140 and Sportsbook B offers the underdog at +155, the combined implied probability is less than 100%. That gap is your guaranteed profit. The execution, however, requires precision, multiple accounts, and an understanding of the risks that most guides gloss over.

This is a complete, practical guide to arbitrage betting in 2026. Not theory. Not hype. The actual mechanics of finding arbs, sizing bets, executing quickly, avoiding account limitations, and building a sustainable arbing operation.

Find and calculate arbitrage opportunities instantly with our Arbitrage Calculator.

What Is Sports Betting Arbitrage?

Arbitrage (arbing) exploits pricing differences between sportsbooks. When the combined implied probability of all outcomes across different books is less than 100%, a guaranteed profit exists.

The Basic Math

Every set of odds implies a probability. For a two-outcome event (like a moneyline):

Sportsbook A: Team X at -140 (implied probability: 58.33%)
Sportsbook B: Team Y at +155 (implied probability: 39.22%)
Combined implied probability: 58.33% + 39.22% = 97.55%

Since the combined probability is less than 100%, an arb exists. The guaranteed profit margin is:

Arb% = (1 - Combined Implied Probability) x 100 = 2.45%

On $1,000 total wagered, that is $24.50 guaranteed profit regardless of who wins.

How to Size Arb Bets

To guarantee equal profit regardless of outcome, you must distribute your total stake proportionally to the implied probabilities.

Formula for each side:

Stake on Outcome A = Total Stake x (Implied Probability of A / Combined Implied Probability)

Using our example ($1,000 total stake):

Stake on Team X at -140: $1,000 x (58.33% / 97.55%) = $598.05
Stake on Team Y at +155: $1,000 x (39.22% / 97.55%) = $401.95

If Team X wins:

Return: $598.05 + ($598.05 / 1.40) = $598.05 + $427.18 = $1,025.23
Profit: $1,025.23 - $1,000 = $25.23

If Team Y wins:

Return: $401.95 x 2.55 = $1,024.97
Profit: $1,024.97 - $1,000 = $24.97

Guaranteed profit of approximately $25 either way. That is the power of arbitrage.

Run these calculations in seconds with our Arbitrage Calculator.

Types of Arbitrage Opportunities

1. Two-Way Arbs (Most Common)

The standard arb described above. Two outcomes, two sportsbooks, guaranteed profit.

Common markets for 2-way arbs:

Moneylines (any sport)
Over/under totals
Point spreads at different numbers
Tennis match winner
Soccer draw-no-bet

2. Three-Way Arbs

Sports with three outcomes (soccer: win, draw, loss) can create 3-way arbs. These are rarer but often more profitable because three-way markets have more pricing inefficiency.

Example: Premier League Match

Sportsbook A: Home win at +180 (implied: 35.71%)
Sportsbook B: Draw at +280 (implied: 26.32%)
Sportsbook C: Away win at +200 (implied: 33.33%)
Combined: 95.36%
Arb margin: 4.64%

That is a juicy 4.64% arb. On $1,000 total wagered, you guarantee approximately $46 profit.

Verify sure bet opportunities across multiple outcomes with our Sure Bet Calculator.

3. Middling (Advanced)

Middling is not pure arbitrage but a closely related strategy. You bet both sides of a point spread at different numbers, creating a window where both bets can win.

Example:

Sportsbook A: Chiefs -3.5 at -110
Sportsbook B: Chiefs +4.5 at -110 (this is the opponent getting 4.5 points)

If the Chiefs win by exactly 4, both bets win. In all other outcomes, one side wins and one loses. Because you are getting +4.5 and -3.5, your worst case is a small loss (the vig on one side), and your best case is a double win.

The math:

Cost of losing one side: ~$4.55 per $100 (the vig)
Probability of middle (landing on 4): ~3-4% for NFL
Payout if middle hits: Win both sides = ~$182 on $200 wagered
EV = (0.035 x $182) - (0.965 x $4.55) = $6.37 - $4.39 = +$1.98 per $200

Middling is +EV even though it is not guaranteed. Over hundreds of attempts, the middles that hit more than compensate for the vig cost.

4. Cross-Market Arbs

These exploit pricing differences between different bet types on the same event.

Example:

Sportsbook A: Over 48.5 total points at -110
Sportsbook B: Team X under 24.5 team total AND Team Y under 24.5 team total (individual team totals)

If the individual team totals are priced softly, you can construct an arb between the game total and the sum of team totals.

Calculate implied probabilities across markets with our Implied Probability Calculator.

How to Find Arbitrage Opportunities

Method 1: Odds Comparison Sites

Dedicated arb-finding services scan dozens of sportsbooks in real time and flag opportunities. These tools are essential for serious arbers because arbs typically last only minutes.

What to look for in an arb scanner:

Coverage of 10+ sportsbooks
Real-time updates (30-second refresh minimum)
Filtering by sport, arb percentage, and sportsbook
Stake calculation built in
Alert system for arbs above your threshold

Method 2: Manual Line Shopping

For casual arbers, manually comparing lines across 5-8 sportsbooks can reveal opportunities, especially in less popular markets.

Markets with frequent arbs:

Early-week NFL lines (before sharp money moves them)
Tennis (fragmented global market)
Soccer (many international books)
Prop bets (less efficiently priced)
Live betting (fast-moving, frequent mispricing)

Method 3: Closing Line Divergence

When one sportsbook is slow to move its line after sharp money hits another book, the old line at the slow book combined with the new line at the sharp book often creates an arb.

Example flow:

Pinnacle moves Bills from -3 to -4 after sharp money
DraftKings still has Bills -3
You bet Bills -3 at DraftKings and the opponent +4 at Pinnacle
If the game lands on 3 or 4 (the middle), both bets win

Compare odds across formats with our Odds Converter.

Executing Arbs: Step-by-Step Process

Step 1: Set Up Multiple Accounts

Serious arbing requires accounts at a minimum of 6-10 sportsbooks. More accounts mean more arb opportunities and better odds selection.

Essential accounts for US-based arbers:

DraftKings (soft lines, slow to move)
FanDuel (frequent promo boosts)
BetMGM (softest lines in many states)
Caesars (aggressive promotions)
PointsBet (unique markets)
Pinnacle (sharp book, low vig, baseline comparison)
BetRivers (decent lines, less restrictive)

Fund each account with enough capital to act on arbs immediately. Having $500-$1,000 per account is a reasonable starting point.

Step 2: Identify the Arb

When your scanner or manual comparison reveals a combined implied probability below 100%:

Verify both lines are still available (lines move fast)
Calculate exact stake for each side
Confirm the arb percentage meets your minimum threshold (most serious arbers require 1%+ to account for execution risk)

Step 3: Place Bets Simultaneously

Speed is critical. Place the bet on the side most likely to move first (usually the sharp book side), then immediately place the other side. The entire execution should take under 60 seconds.

Execution order best practice:

Open both sportsbook apps/sites
Pre-fill bet slips with calculated amounts
Place the side at the sharper book first
Immediately confirm the other side
Verify both bets are confirmed at the expected odds

Step 4: Verify and Record

After both bets are placed:

Screenshot both bet confirmations
Record in your arb tracking spreadsheet: date, event, Book A odds, Book B odds, stake A, stake B, guaranteed profit, actual outcome
Calculate your actual ROI to track performance

Calculate the exact vig you are exploiting with our Hold/Vig Calculator.

Real-World Arbitrage Examples

Example 1: NFL Moneyline Arb

You find the following on Monday Night Football:

DraftKings: Cowboys +145 (implied: 40.82%)
Pinnacle: Eagles -135 (implied: 57.45%)
Combined: 98.27%
Arb margin: 1.73%

Sizing on $2,000 total:

Cowboys at DraftKings: $2,000 x (40.82 / 98.27) = $831.47
Eagles at Pinnacle: $2,000 x (57.45 / 98.27) = $1,168.53

If Cowboys win: $831.47 x 2.45 = $2,037.10. Profit: $37.10 If Eagles win: $1,168.53 x 1.741 = $2,034.37. Profit: $34.37

Guaranteed profit of $34-$37 on zero risk. Execute this 3-4 times per week and you are making $400-$600 per month.

Example 2: Tennis Three-Way Set Betting Arb

Grand Slam tennis set betting often creates 3-way arbs:

Bet365: Player A in straight sets at +200 (implied: 33.33%)
Pinnacle: Player B in straight sets at +250 (implied: 28.57%)
DraftKings: Match to go 3 sets at +150 (implied: 40.00%)
Combined: 101.90%

Wait, that is over 100%. No arb exists. But if you find:

Player A in straight sets: +200 (33.33%)
Player B in straight sets: +300 (25.00%)
Match to go 3 sets: +175 (36.36%)
Combined: 94.69%
Arb margin: 5.31%

On $1,500 total, guaranteed profit of approximately $79.65.

Example 3: Live Betting Arb During Score Change

A basketball game sees the home team go on a 10-0 run. Sportsbook A adjusts the live spread instantly to Home -8.5. Sportsbook B is slow to update and still shows Home -4.5.

You bet Away +8.5 at Sportsbook A (-110) and Home -4.5 at Sportsbook B (-110).

If the final margin lands between 5 and 8: Both bets win (the middle)
If the margin is 4 or less: Away +8.5 wins, Home -4.5 loses (small vig loss)
If the margin is 9+: Home -4.5 wins, Away +8.5 loses (small vig loss)

The 4-point middle window in a basketball game has roughly a 15% probability. This is massively +EV:

EV = (0.15 x $182) - (0.85 x $4.55) = $27.30 - $3.87 = +$23.43 per $200

Live middles are the most profitable arb-adjacent strategy in sports betting.

Example 4: Promotion Arbitrage

Sportsbook runs a "Bet $500, get $200 in free bets" promotion. You arb the qualifying bet:

Qualifying bet: $500 on Team A at -110 (Sportsbook with promo)
Hedge: $485 on Team B at +105 (Another sportsbook)
Total outlay: $985

If Team A wins: $500 + $454.55 = $954.55. Loss of $30.45. But you receive $200 in free bets. If Team B wins: $485 + $509.25 = $994.25. Profit of $9.25. Plus $200 in free bets.

The free bets convert at approximately 70% ($140 value). Net profit either way: $109-$149.

Calculate matched betting profits with our Matched Betting Calculator.

Example 5: Alternate Spread Arbitrage

Books sometimes misprice alternate spreads:

FanDuel: Patriots +10.5 at -180 (implied: 64.29%)
BetMGM: Bills -10.5 at +175 (implied: 36.36%)
Combined: 100.65%

No arb at these prices. But then BetMGM boosts Bills -10.5 to +200:

BetMGM: Bills -10.5 at +200 (implied: 33.33%)
Combined: 64.29% + 33.33% = 97.62%
Arb margin: 2.38%

Boosts on alternate lines are a goldmine for arbers because they create arbs that would not otherwise exist.

Convert free bet value precisely with our Free Bet Calculator (SNR).

Example 6: The Cross-Market Middle

You find a soccer game where:

Sportsbook A: Over 2.5 goals at -105 (implied: 51.22%)
Sportsbook B: Under 3.5 goals at -125 (implied: 55.56%)
Combined: 106.78%

No straight arb. But if the game finishes with exactly 3 goals, both bets win. The probability of exactly 3 goals in a soccer game is roughly 20-25%.

Cost if no middle: The worse side loses ~$2.50 per $100. Gain if middle hits: Both win, collecting ~$190 on $200 wagered.

EV = (0.22 x $190) - (0.78 x $2.50) = $41.80 - $1.95 = +$39.85 per $200

This is not a guaranteed arb but an extremely +EV middle opportunity.

Risks and Challenges of Arbitrage Betting

Account Limitations and Bans

This is the biggest practical challenge. Sportsbooks lose money to arbers, and they actively identify and limit sharp accounts.

Signs your account is being reviewed:

Maximum bet amounts decrease
Odds change after you place a bet (dynamic pricing)
Promotions stop appearing on your account
Bet approval becomes delayed

How to delay limitations:

Round your bet amounts (bet $500 instead of $498.73)
Mix in recreational bets on popular markets
Do not always bet the maximum
Spread arb activity across many sportsbooks
Use promotions to look like a recreational bettor
Avoid arbing the same market type repeatedly

Line Movement Risk

Between placing your first and second leg, the line may move, killing the arb.

Mitigation strategies:

Place the softer (more likely to move) side first
Pre-fill both bet slips before confirming either
Only pursue arbs with margins above 1.5% to absorb potential slippage
Have fast internet and multiple devices ready

Cancelled Bets

Sportsbooks can void bets if they determine a line was posted in error ("palpable error"). If one side of your arb is cancelled, you are left with a naked position.

Protection:

Avoid arbs based on obvious errors (e.g., a line that is 20+ points off the market)
Keep capital reserved to hedge a remaining position if one side is voided
Document everything in case you need to dispute

Bankroll Lockup

Arb betting ties up significant capital for small returns. If you have $10,000 spread across 10 accounts ($1,000 each), and arbs yield 2% per turnover, you need to cycle that capital many times per month to generate meaningful profit.

Capital efficiency:

Target 3-5 arb cycles per week per account
Withdraw profits regularly to reduce exposure risk
Keep records of all deposits and withdrawals

Monitor your arbitrage bankroll performance with our Bankroll Volatility Tracker.

Realistic Profit Expectations

Arbitrage betting is not a get-rich-quick scheme. Here are realistic numbers based on capital deployment.

Monthly Profit Estimates

Starting Capital	Accounts	Avg Arb %	Cycles/Week	Monthly Profit
$2,000	4	1.5%	3	$360
$5,000	6	1.8%	4	$1,440
$10,000	8	2.0%	5	$4,000
$25,000	10	2.0%	5	$10,000
$50,000	12+	2.0%	5	$20,000

These assume consistent execution, no voided bets, and not getting limited. In practice, account limitations reduce monthly profits by 20-30% as you lose access to soft books.

Time Investment

Activity	Time per Week
Scanning for arbs	5-10 hours
Executing arbs	2-4 hours
Account management	1-2 hours
Record keeping	1 hour
Total	9-17 hours

At $1,440/month profit on $5,000 capital, that is roughly $85-$160 per hour of active work. Not bad for risk-free income.

Dutching: The Arb-Adjacent Strategy

Dutching is similar to arbitrage but involves spreading bets across multiple outcomes at a single sportsbook. While it does not guarantee profit (one book's combined implied probability is always over 100%), it can reduce risk and exploit situations where one outcome is significantly overpriced.

When dutching makes sense:

You believe one outcome has a much higher probability than the book implies
You want to reduce variance on an event with multiple possible outcomes
You are using promotional offers that apply to a specific sportsbook

Calculate optimal dutching stakes with our Dutching Calculator.

Arbitrage vs. Other Advantage Strategies

Strategy	Risk Level	Monthly Return (on capital)	Skill Required	Time Investment
Arbitrage	Near-zero	3-8%	Low (math only)	High
Matched Betting	Near-zero	5-15% (on promos)	Low-medium	Medium
+EV Betting	Medium	2-5% (of handle)	High	Medium-high
Middling	Low	1-3%	Medium	Medium
Promotion Exploitation	Low	Variable (promo-dependent)	Low	Low

Arbitrage has the lowest risk but requires the most capital and time. Many advantage bettors combine arbing with matched betting and +EV betting for maximum returns.

Calculate expected value on any individual bet with our Expected Value Calculator.

Frequently Asked Questions

Is sports betting arbitrage legal? Yes. Arbitrage betting is completely legal in every US state where sports betting is legal. You are simply placing bets at two different sportsbooks. However, sportsbooks may limit or close your account for suspected arbing, as it is against most books' terms of service to use accounts primarily for arbitrage.

How much money do I need to start arbitrage betting? A practical minimum is $2,000-$3,000 spread across 4-6 sportsbook accounts. This gives you $400-$500 per account, enough to execute arbs of $200-$500 total. With 1-2% margins, that is $2-$10 per arb, which adds up with volume. Use our Arbitrage Calculator to size bets correctly.

How often do arbitrage opportunities appear? Multiple times per day, especially around line opens and during live betting. NFL Sundays can produce 10-20+ arb opportunities across different games. Less popular sports like tennis and international soccer often have larger arb margins but lower betting limits.

Will sportsbooks ban me for arbitrage betting? They will not ban you from the platform, but they will limit your maximum bet amounts, sometimes to as low as $5-$10 per bet. This effectively ends your ability to arb on that account. Strategies to delay this include rounding bet amounts, mixing in recreational activity, and spreading bets across many books.

What is the difference between arbitrage and middling? Arbitrage guarantees profit on every execution. Middling bets both sides at different numbers, creating a window where both can win. Middling is not guaranteed per-bet but is +EV over large samples. Our Hedge Calculator handles both scenarios.

Can I automate arbitrage betting? Arb scanning can be automated with subscription services. Bet placement automation is against most sportsbooks' terms of service and can result in immediate account closure. Most successful arbers use automated scanning but manual execution.

What is the average arbitrage profit margin? Most arb opportunities in US sports betting carry 1-3% margins. Three-way markets (soccer) can offer 3-5%. Promotional arbs (exploiting boosts and free bets) often yield 5-15% effective margins. Check margins with our Sure Bet Calculator.

How do I handle a voided bet on one side of an arb? You are now exposed on the remaining side. Immediately assess whether to hedge the remaining bet on another sportsbook, let it ride if the odds are favorable, or accept the single-bet risk. Always have capital reserved for this contingency.

Essential Tools for Arbitrage Bettors

Core Arbitrage Tools

Arbitrage Calculator: Calculate exact stake distribution and guaranteed profit for any arb opportunity
Sure Bet Calculator: Verify whether a combination of odds across sportsbooks constitutes a sure bet
Odds Converter: Convert between American, decimal, and fractional odds for accurate cross-book comparison
Hedge Calculator: Calculate optimal hedge positions for middling and partial arb strategies

Profit Optimization Tools

Matched Betting Calculator: Maximize profit extraction from sportsbook promotions through hedged bets
Free Bet Calculator (SNR): Calculate the true value of stake-not-returned free bet promotions
Hold/Vig Calculator: Identify which sportsbooks have the softest lines (highest vig) to find arb opportunities
Dutching Calculator: Optimize stake distribution when spreading bets across multiple outcomes

Analysis and Tracking Tools

Expected Value Calculator: Evaluate the EV of middling and non-guaranteed arb strategies
Implied Probability Calculator: Convert any odds to implied probability for quick arb identification
Bankroll Volatility Tracker: Monitor your arb bankroll across multiple sportsbook accounts

Conclusion: Building a Sustainable Arb Operation

Arbitrage betting is the lowest-risk advantage play in sports betting. The math is straightforward, the execution is mechanical, and the profits are guaranteed per-transaction. But sustainability is the real challenge. Account limitations will reduce your capacity over time, and the operational overhead of managing many accounts, executing quickly, and tracking everything adds up.

The most successful arbers treat it as a business. They diversify across arbitrage, matched betting, and +EV betting. They reinvest profits to increase capital base. And they accept that individual accounts have a limited lifespan, constantly signing up for new books and promotions to replace limited accounts.

Start with 4-6 accounts and $2,000-$5,000. Learn the mechanics on small arbs. Build speed and confidence. Scale up as your process tightens. The money is real, but the window at each sportsbook is finite.

Begin finding arbs today with our Arbitrage Calculator. Verify opportunities with our Sure Bet Calculator. And convert promotions into guaranteed profit with our Matched Betting Calculator.

Gambling involves risk. This content is for educational and informational purposes only. Always gamble responsibly, set limits you can afford, and seek help if gambling becomes a problem. Visit the National Council on Problem Gambling or call 1-800-522-4700 for support.